Composite modified double base (CMDB) propellants are heterogeneous propellants in which properties are significantly improved by adding solid particles into the polymer matrix. A molecular group interaction model that can predict the mechanical properties of polymers through a molecular structure is used to predict the viscoelastic behavior of the CMDB propellant. Considering that the addition of solid particles will improve the crosslinking degree between polymer molecules and reduce its secondary loss peak, the input parameters of the model are modified through dynamic mechanical analysis (DMA) experimental data. By introducing the strain rate into the expression of model glass transition temperature, the mechanical properties of propellant over a wide strain range ( s^-1 ~ 3000 s^-1) are obtained. The reliability of the model is verified by comparison with uniaxial compression test data. By modifying the input parameters of the model, the effects of different mass ratios of nitrocellulose (NC)/nitroglycerin (NG) on the mechanical properties of the CMDB propellant were analyzed. The results show that the glass transition loss increases with increasing mass ratio of NC/NG, while Young’s modulus and yield stress decrease.

中文翻译：

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使用群相互作用模型研究 CMDB 推进剂在宽应变率范围内的力学性能

复合改性双基 (CMDB) 推进剂是一种异质推进剂，通过在聚合物基体中添加固体颗粒可显着改善其性能。通过分子结构可以预测聚合物力学性能的分子基团相互作用模型用于预测CMDB推进剂的粘弹性行为。考虑到固体颗粒的加入会提高聚合物分子间的交联度，降低其二次损失峰，通过动态力学分析（DMA）实验数据对模型的输入参数进行修正。通过将应变速率引入模型玻璃化转变温度的表达式中，推进剂在宽应变范围内的力学性能（ s ^-1  ~ 3000 s ^-1 )。通过与单轴压缩试验数据的对比，验证了模型的可靠性。通过修改模型的输入参数，分析了硝酸纤维素（NC）/硝酸甘油（NG）不同质量比对CMDB推进剂力学性能的影响。结果表明，随着NC/NG质量比的增加，玻璃化转变损失增加，而杨氏模量和屈服应力降低。